Hi, don't worry for asking :)
The rpg maker VX Ace has pretty rigid size restrictions, here they are:
A1 and A2 are 512 x 384 pixels
A3 is 512 x 256 pixels
A4 is 512 x 480 pixels
A5 is 256 x 512 pixels
B-E Tilesets are 512 x 512 pixels.
I'm not sure for D and E
It's hard for me to prepare the files so they can fit any particular requirment of every game engine, but tomorrow I'll chop everything to fit 512x512 size, so it'll be easier anyone using the VX Ace like you, don't worry ;)